Background

Scutellarin, an herbal compound, can effectively suppress the inflammatory response in activated microglia/brain macrophage(AM/BM) in experimentally induced cerebral ischemia; however, the underlying mechanism for this has not been fully clarified. We sought to elucidate if scutellarin would exert its anti-inflammatory effects on AM/BM through the MAPKs pathway.

Materials and Methods

Western blot and immunofluorescence labeling were used to determine the expression of the MAPKs pathway in AM/BM in rats subjected to middle cerebral artery occlusion (MCAO) also in lipopolysaccharide (LPS)-activated BV-2 microglia in vitro. Furthermore, expression of p-p38 along with that of tumor necrosis factor-alpha (TNF-α), interleukin-1 beta(IL-1β), and inducible nitric oxide synthase (iNOS) in LPS-activated microglia subjected to pretreatment with p38 inhibitor SB203580, p38 activator sc-201214, scutellarin, or a combination of them was evaluated.

Findings

Scutellarin markedly attenuated the expression of p-p38, p-JNK in AM/BM in MCAO rats and in vitro. Conversely, p-ERK1/2 expression level was significantly increased by scutellarin. Meanwhile, scutellarin suppressed the expression of proinflammatory mediators including iNOS, TNF-α, and IL-1β in AM/BM. More importantly, SB203580 suppressed p-p38 protein expression level in LPS-activated BV-2 microglia that was coupled with decreased expression of proinflammatory mediators (TNF-α, iNOS) in LPS-activated BV-2 microglia. However, p38 activator sc-201214 increased expression of proinflammatory mediators TNF-α, iNOS, and IL-1β. Interestingly, the decreased expression of both proinflammatory markers by p38 MAPK inhibitor and increased expression of proinflammatory markers by p38 MAPK activator were compatible with that in BV-2-activated microglia pretreated with scutellarin.

Conclusions

The results suggest that scutellarin down-regulates the expression of proinflammatory mediators in AM/BM through suppressing the p-JNK and p-p38 MAPKs. Of note, the anti-inflammatory effect of p38 MAPK inhibitor and scutellarin is comparable. Besides, p38 MAPKs activator reverses the effect of scutellarin. Additionally, scutellarin increases p-ERK1/2 expression that may be neuroprotective.

中文翻译：

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黄cut苷通过调节MAPKs信号通路在脑缺血和BV-2小胶质细胞活化的小胶质细胞/脑巨噬细胞中发挥抗炎作用。

背景

黄cut素是一种草药，可有效抑制活化的小胶质细胞/脑巨噬细胞（AM / BM）在实验性脑缺血中的炎症反应。但是，尚未完全阐明其基本机制。我们试图阐明黄苷是否会通过MAPKs途径对AM / BM发挥抗炎作用。

材料和方法

免疫印迹和免疫荧光标记被用来确定MAPKs通路在大鼠中脑动脉闭塞（MCAO）和脂多糖（LPS）激活的BV-2小胶质细胞中在AM / BM中的表达。此外，在经过p38预处理的LPS激活的小胶质细胞中，p-p38以及肿瘤坏死因子-α（TNF-α），白介素-1 beta（IL-1β）和诱导型一氧化氮合酶（iNOS）的表达评价了抑制剂SB203580，p38激活剂sc-201214，scutellarin或它们的组合。

发现

黄cut苷可显着减弱MCAO大鼠和体外AM / BM中p-p38，p-JNK的表达。相反，黄cut苷可显着提高p-ERK1 / 2表达水平。同时，scutellarin抑制了AM / BM中促炎性介质iNOS，TNF-α和IL-1β的表达。更重要的是，SB203580抑制了LPS激活的BV-2小胶质细胞中p-p38蛋白的表达水平，同时还降低了LPS激活的BV-2小胶质细胞中促炎性介质（TNF-α，iNOS）的表达。但是，p38激活剂sc-201214增加了促炎性介质TNF-α，iNOS和IL-1β的表达。有趣的是

结论

结果表明，黄cut苷可通过抑制p-JNK和p-p38 MAPKs下调AM / BM中促炎性介质的表达。值得注意的是，p38 MAPK抑制剂和黄cut苷的抗炎作用相当。此外，p38 MAPKs激活剂可逆转黄cut苷的作用。此外，盾cut增加可能具有神经保护作用的p-ERK1 / 2表达。